Filter dryers in refrigerant recovery units are used to trap acid, moisture, or particulates as the refrigerant passes through the filter dryers. These filter dryers, typically, have a maximum capacity to trap these contaminants. In order for the refrigerant recovery unit to function properly, these filter dryers need to be replaced periodically to ensure the refrigerant is cleaned upon the recovery/recycle process. Otherwise, continued use of the saturated filter dryers can be damaging to the air conditioning system.
Currently, a user is prompted to change the filter dryer when a predetermined amount of refrigerant has passed through the filter dryer, such as one-hundred and fifty pounds. However, the user may simply ignore the notification by pushing a button indicating that he has changed the filter dryer and continues to use the expired filter dryer for the recovery/recycle process. Furthermore, the counter will reset to zero and the notification will not be activated until another one-hundred and fifty pounds of refrigerant has passed through the filter dryer. Thus, the refrigerant passing through the filter dryer will not be cleaned properly upon the recovery/recycle process.
Accordingly, it is desirable to provide a method and apparatus to ensure that a user performs filter dryer maintenance for a refrigerant recovery unit when the filter dryer needs to be replaced.